Fuel feed devices for internal combustion engines

ABSTRACT

Valves supplied from a source of fuel under pressure are each actuated by an electromagnet energized over a variable fraction of each revolution of a rotary member driven by the engine. The energizing current is governed by a light source which illuminates a photo-sensitive element according to the position of an intermediate rotary member. The fuel is fed to the valve by a fuel pump whose delivery circuit includes a pressure regulator comprising a discharge valve controlled by the suction in the intake pipe of the engine. Variation of richness of the air/fuel mixture through temperature changes is compensated by a bimetallic element coupled to the discharge valve.

United States Patent Mennesson 1 5] Feb. 6, 1973 541 FUEL FEED DEVICESFOR INTERNAL 2,921,569 1/1960 Gold ..123 140 MC COMBUSTION ENGINES2,876,758 3/1959 Armstrong ..l23/l79 A 2,161,743 6/[939 Heinrichet'al... ..l23/l40 MC [75] Inv n or: Francois Menness'on, 92 Nanterr3.620.202 11 1971 Ross ..123 119 R X France [73] Assigncc: Societelndustrielle de Brevets ct f 'i smith dEmdes SDI'BE. Ncumy sur scincASSISIHNI bxammer-Denms Toth France A/mrney-Stevens, Davis, Miller &Mosher [22] Filed: Sept. 7, 1971 [57] ABSTRACT 21 1 NO l782l7 Valvessupphed from a source of fuel under pressure are each actuated by anelectromagnet energized over [30] Foreign Application Priority Data avariable fraction of each revolution of a rotary member driven by theengine. The energizing current Sept. 15, 1970 France ..703345l isgoverned y a light Source which illuminates a photo-sensitive elementaccording to the position of [52] Cl "123/139 k fi g an intermediaterotary member. The fuel is fed to the [51] Int Cl Fozm 51/02 1. 39/00valve by a fuel pump whose delivery circuit includes a [58] Fieid Aw 14039 AF pressure regulator comprising a discharge valve con- {23/1 19trolled by the suction in the intake pipe of the engine. Variation ofrichness of the air/fuel mixture through temperature changes iscompensated by a bimetallic [56] References Clted element coupled to thedischarge valve.

UNITED STATES PATENTS 3,596,645 8/1971 Mennesson ..123 139 AW 2 Clams 2D'awmg figures 3.714.934 SHEET 10F 2 PATENTED FEB 6 I975 FUEL FEEDDEVICES FOR INTERNAL COMBUSTION ENGINES The invention relates to fuelfeed devices for internal combustion engines, of the type whichcomprise, on the one hand, in their inlet conduit, upstream of anprincipal throttle member actuated by the driver, an auxiliary throttlemember which opens automatically and progressively in proportion as theair flow rate in the said conduit increases, on the other hand, meansfor injecting under pressure liquid fuel into the portion of thisconduit situated downstream of the principal throttle member, and, onthe other hand lastly, a metering system sensitive to the position ofthe auxiliary throttle member and adapted to regulate the flow-rate ofthe fuel injected in such a way that the richness of the air/fuelmixture passing into the inlet conduit is substantially constant, atleast under certain conditions of operation of the engine, the abovesaidinjection means being constituted by a source of fuel under pressurewhose delivery circuit, opening into the above-said portion of the inletconduit, is controlled by at least one valve actuated by anelectromagnet.

The invention relates more particularly to those of the devices of thetype concerned which have been described in applicants Pat. No.3,543,739 and of which the above-said metering system comprises a memberdriven in continuous rotary movement and capable, by acting on theenergization of the electromagnet, of determining over a fraction onlyof each of its revolutions the opening of the valve, the system beingarranged so that it increases the said fraction in proportion as theopening of the auxiliary throttle member increases and vice-versa.

The invention relates more particularly again to those devices of thetype concerned of which the source of fuel under pressure is constitutedby a fuel pump in the delivery pipe of which acts a pressure regulatorwhich comprises a relief valve tending to open under the effect of thedelivery pressure of the pump and to close under the effect of thesuction existing in the section of the inlet conduit comprised betweenits two throttle members, which suction is transmitted by a connectingpassage to a diaphragm to which is coupled the relief valve.

Of course the position of the auxiliary throttle member ischaracteristic of the flow-rate of the air passing from upstream todownstream of this member, provided that the density of the air ispractically constant.

However, for large variations of temperature of the air, the variationof its density becomes important and the position of the auxiliarythrottle member no longer gives accurate indication of the air flow-ratein terms of mass passing from upstream to downstream of this throttlemember. In fact, for a given position of'the latter and hence for anidentical fuel flow-rate (provided that the temperature of the latter isconstant), the air flow-rate in terms of mass passing from upstream todownstream of the auxiliary throttle member is all the greater as theair temperature is lower.

Additionally, the fuel flow-rate through a calibrated orifice tends toincrease if the temperature of this fuel increases as a result of thedecrease in its viscosity. An increase in ambient temperature, hence anincrease in the temperature of the fuel, is manifested consequently,also, by an increase in fuel flow-rate.

As a result, at low ambient temperatures, the richness of the air/fuelmixture passing in the inlet conduit is too weak and, on the other hand,at high temperatures, the richness of the mixture is too strong.

With the object of overcoming this drawback, the fuel supply device ofthe type defined above is characterized by the fact that an elasticelement, deformable under the effect of the temperature variation,exerts on the discharge valve of the above-said pressure regulator aforce directed in the sense of its closing which increases (in algebraicvalue) in proportion as the temperature drops. The said element can beadjusted so that, for an average position of-the discharge valve, theforce that it exerts is null for an average temperature range and tendsto close the valve or to open it according as its temperature is belowor above this temperature range. In this latter case, the force directedin the sense of closing is considered by convention asa negative force.

The fuel flow-rate is thus modified by acting on the injection pressure,so that the richness of the air/fuel mixture passing in the inletconduit remains substantially constant, even for considerable variationsin the air temperature.

The invention will, in any case, be well understood by means of thefollowing complementary description, as well as from the accompanyingdrawings, which complementary description and drawings relate to apreferred embodiment, given purely by way of illustrative andnon-limiting example.

In these drawings,

FIG. 1 shows, in diagrammatic elevation with portions cut out, oneembodiment of the fuel feed device constructed according to theinvention FIG. 2 shows a section along the line II-Il of FIG. 1.

According to the invention, and more particularly according to that ofits methods of application, as well as according to those of its methodsof production of the various parts, to which it would appear thatpreference should be given, in order to contruct a fuel feed device forautomobile engines or the like, procedure is as follows.

As regards the device as the whole, it is constituted in any suitablemanner so that it comprises on the one hand, in its inlet conduit 1,upstream of a principal throttle member 2 actuated by the driver, anauxiliary throttle member 3 which opens automatically and progressivelyin proportion as the air flowrate in the conduit 1 increases, thedirection of flow being indicated by the arrow F in FIG. 1

on the other hand, means for injecting under pressure liquid fuel intothe portion of the conduit 1 situated downstream of the principalthrottle member 2 on the other hand, lastly, a metering system sensitiveto the position of the auxiliary throttle member 3 and adapted toregulate the flow-rate of injected fuel in such a way that the richnessof the air/fuel mixture passing in the conduit 1 is substantiallyconstant, at least for certain conditions of operation of the engine.

In the embodiment shown, the auxiliary throttle member 3 is constitutedby a butterfly-valve fixed on an axle 4. This butterfly-valve isactuated by a pneumatic device comprising a diaphragm 5 separating twochambers 6 and 7 from one another. The chamber 6 is connected by apassage 8 to a chamber 9 constituted by the section of the conduit 1which is comprised between the principal throttle member 2 and the valve3. The axle 4 is rigidly fixed to a lever provided, at its free end,with a pin 11 which cooperates with the end of a rod 12, which isconnected to the diaphragm 5. Spring 13 tends constantly to close thevalve 3 against the effect of the suction transmitted in the chamber 6.The chamber 7 is placed at atmospheric pressure by passage 14 startingpreferably from the air intake 15 of the conduit 1.

Of course the angular position adopted at any moment inside the conduit1 by the valve 3 corresponds to the air flow-rate which circulates inthis conduit, as long as the density of the air remains practicallyconstant. The greater the air flow-rate the more the valve 3 opens, asubstantially constant suction (or varying according to thecharacteristics of the spring 13) being established in the chamber 9comprised between the two throttle members 2 and 3. The valve 3 could bereplaced by equivalent throttle members, of which examples have beendescribed in the abovesaid patent and its first certificate of addition.

The above-said injection means is constituted by source of fuel underpressure which will be described in more detail below and which thedelivery circuit, opening into the conduit 1 downstream of the principalthrottle member 2, is constrolled by at least one valve 16 actuated byan electromagnet 17.

The metering system comprises a flattened opaque disc 18 which is borneby a shaft 19, connected preferably to the internal combustion engine(not shown) supplied by the device, so that the disc is driven in acontinuous movement of rotation around an axis perpendicular to itsplane. The disc 18 is interposed between a source of radiation,especially a light source 20 and a receiver such as a photodiode or aphotoelectric cell 21, borne by a common support 22 connected to theauxiliary throttle member 3 and it is pierced by at least one aperture23 adapted to allow the beam coming from source 20 to arrive at cell 21.Cell 21 is arranged to control the energization the electromagnet 17according as it is irradiated or not and the assembly is such that theelectromagnet is energized over a fraction of each of the revolutions ofdisc 18 which varies in the same sense as the degree of opening of thethrottle member 3.

The light source 20 may be constituted by a lamp which is adapted to besupplied by a battery 24 as soon as the ignition contact 25 of theengine is closed and which is arranged in a hollow boss 26 pierced by ahole. This hole is oriented in such a way as to direct a light beam ontothe cell 21, through a hole passing through a hollow boss 27 wherein thesaid cell is lodged. in the embodiment shown, the bosses 26 and 27 aremade to be carried by the ends of the U-shaped support 22 whichstraddles the disc 18 so that the source 20 and the cell 21 occur oneach of the disc and which is rigidly fixed to the axle 4, the latterbeing parallel to the shaft 19 as well as to the light beam received bythe cell 21.

To apply the currents generated in the cell 21, there is interposedbetween the latter and the electromagnet 17, an amplifying relay 28.

When the internal combustion engine has several cylinders supplied by avalve 16 actuated by an individual electromagnet 17, all theelectromagnets can be actuated simultaneously or a distributor 30 can beprovided synchronized with the disc 18 to send successively intermittentenergizing current into the various electromagnets, the disc possessingas many apertures 23 as cylinders to be supplied. The apertures aredistributed regularly around the shaft 19 and have each a shape suchthat the fraction of the revolution during which it normally permits thecell 21 to be illuminated increases in proportion as the throttle member3 opens, that is to say (in the embodiment shown) in proportion as thebosses 26, 27 approach the shaft 19.

Of course the fuel feed device which has just been described operates asfollows.

In proportion as the air flow-rate in the conduit 1 increases, thethrottle member 3 opens thereby driving the support 22 in the sensewhich brings closer together the shaft 19 and the bosses 26 and 27. Eachof the positions of the bosses corresponds to a different radius of thedisc 18.

Since the shape of each aperture 23 has been determined so that thefraction of a revolution, during which it allows to pass towards thecell 21 the light ray coming from the source 20 (creation of a currentin the conductor 3l),.increases in proportion as the latter elementsapproach the shaft 19, it is insured that the fuel flow-rate deliveredby each injection valve 16 varies in the same sense as the air flow-ratein conduit 1.

This being so the source of liquid fuel under pressure is constituted bya fuel p mp of which the intake pipe 51 dips into a fuel reservoir 52and on the delivery pipe 53 of which acts a pressure regulator 54. The

latter comprises a relief valve 55 tending to open under the effect ofthe delivery pressure of the pump and to close under the effect of thesuction existing in the chamber 9, which suction is transmitted by aconnecting passage 56 to a diaphragm 57 to which is coupled the valve 55by a rod 58. The valve 55 cooperates with a seat 59 which constitutesthe'exit of a chamber 60 connected through a branch channel 61 to thedelivery pipe 53. The connecting passage 56 ends in a variable volumechamber 62 bounded by one surface of the diaphragm, the other surfacebeing placed at atmospheric pressure for example through an orifice 63.The whole is such that the valve 55 opens as soon as the pressure in thepipe 53 exceeds a value determined by the surface of the diaphragm 57and by the suction exerting on the latter.

According to the invention, recourse is had to an element, elastic anddeformable under the effect of temperature variation, such that abimetallic strip 83. One of the ends of this strip is fixed on the bodyof the regu? lator 54, the other end is coupled to the rod 58. Thuspositioned, the strip 83 has a temperature which depends on that of theambient air and of the fuel, due to the fact of thermal conduction inthe regulator. lt-is arranged so that, on an increase in temperature,the bimetallic strip 83 has a tendency to open the valve 55.

The operation of the regulator according to the present improvement isas follows As explained above, for a same position of the auxiliarythrottle member 3, the air flow-rate by weight passing in the inletconduit 1 is greater or less according as the air temperature is higheror lower, and the fuel flow-rate is greater or less according as itstemperature is higher or lower. To maintain an approximately constantair/fuel mixture richness, the bimetallic strip 83 serves to increasethe fuel flow-rate if the temperature decreases and to reduce the fuelflow-rate if the temperature increases.

In fact, for a drop in temperature, the effort of the bimetallic strip83 is added to that exerted by the diaphragm 57 under the effect of thesuction in the chamber 62 and tends to close the valve 55 a little more,which causes an increase in fuel pressure upstream of the injectionorifice actuated by the valve 16, and consequently an increase in theflow-rate of the fuel in the inlet conduit 1.

A reverse effect is obtained for an increase of temperature.

This correction in the richness of the air/fuel mixture is all moreeffective as the air flow-rate in the conduit 1 is less, but inpractice, this correction is not generally necessary for high airflow-rates.

As is self-evident, and as emerges already from the foregoing, theinvention is in no way limited to those of its methods of application,nor to those of its methods of production of its various parts, whichhave been more especially indicated it encompasses, on the contrary, allvariations. In particular, the bimetallic strip 83 may be replaced byany other element, elastic and deformable under the effect oftemperature variation.

1 claim 1. Fuel feed device, for an internal combustion engine,comprising in an inlet conduit, upstream ofa principal throttle memberadapted to be actuated by the operator, an auxiliary throttle memberwhich opens automatically and progressively as the air-flow rate in saidconduit increases, and means for injecting liquid fuel under pressureinto the portion of this conduit situated downstream of the principalthrottle member and, a metering system sensitive to the position of theauxiliary throttle member and adapted to regulate the flowrate of thefuel injected in such a way that the richness of the air/fuel mixturepassing in the inlet conduit is substantially constant, at least forcertain conditions of operation of the engine, the above-said injectionmeans being constituted by a source of fuel under pressure of which thedelivery circuit opening into the said portion of the inlet conduit iscontrolled by at least one valve actuated by an electromagnet, themetering system comprising a member driven in a movement of continuousrotation and capable, by acting on the energization of theelectromagnet, of determining over a fraction only of each of theserevolutions, the opening of the valve, said system being arranged sothat it increases the said fraction in proportion as the opening of theauxiliary throttle member increases and vice-versa, the said source offuel under pressure being constituted by a fuel pump in whose deliverycircuit acts a pressure regulator which comprises a relief valve tendingto open under the action of the delivery pressure of the pump and toclose under the action of the suction existing in the section of theinlet conduit comprised between its two throttle members, which suctionis transmitted through a connecting passage to a diaphragm to which therelief valve is coupled, characterized by the fact that an elasticelement which engages said relief valve and is deformable under theeffect of the variation of temperature, is arranged to exert on saidrelief valve, a force directed in the sense of its closing whichincreases (in algebraic value) in proportion as the temperaturedecreases.

2. Fuel feed device according to claim 1, wherein said elastic elementis adjusted in such a way that, for an average position of the reliefvalve, the force that it exerts is nil for an average temperature rangeand tends to close the valve or to open it according as its temperatureis respectively below or above said temperature range.

1. Fuel feed device, for an internal combustion engine, comprising in aninlet conduit, upstream of a principal throttle member adapted to beactuated by the operator, an auxiliary throttle member which opensautomatically and progressively as the air-flow rate in said conduitincreases, and means for injecting liquid fuel under pressure into theportion of this conduit situated downstream of the principal throttlemember and, a metering system sensitive to the position of the auxiliarythrottle member and adapted to regulate the flow-rate of the fuelinjected in such a way that the richness of the air/fuel mixture passingin the inlet conduit is substantially constant, at least for certainconditions of operation of the engine, the above-said injection meansbeing constituted by a source of fuel under pressure of which thedelivery circuit opening into the said portion of the inlet conduit iscontrolled by at least one valve actuated by an electromagnet, themetering system comprising a member driven in a movement of continuousrotation and capable, by acting on the energization of theelectromagnet, of determining over a fraction only of each of theserevolutions, the opening of the valve, said system being arranged sothat it increases the said fraction in proportion as the opening of theauxiliary throttle member increases and vice-versa, the said source offuel under pressure being constituted by a fuel pump in whose deliverycircuit acts a pressure regulator which comprises a relief valve tendingto open under the action of the delivery pressure of the pump and toclose under the action of the suction existing in the section of theinlet conduit comprised between its two throttle members, which suctionis transmitted through a connecting passage to a diaphragm to which therelief valve is coupled, characterized by the fact that an elasticelement which engages said relief valve and is deformable under theeffect of the variation of temperature, is arranged to exert on saidrelief valve, a force directed in the sense of its closing whichincreases (in algebraic value) in proportion as the temperaturedecreases.
 1. Fuel feed device, for an internal combustion engine,comprising in an inlet conduit, upstream of a principal throttle memberadapted to be actuated by the operator, an auxiliary throttle memberwhich opens automatically and progressively as the air-flow rate in saidconduit increases, and means for injecting liquid fuel under pressureinto the portion of this conduit situated downstream of the principalthrottle member and, a metering system sensitive to the position of theauxiliary throttle member and adapted to regulate the flow-rate of thefuel injected in such a way that the richness of the air/fuel mixturepassing in the inlet conduit is substantially constant, at least forcertain conditions of operation of the engine, the above-said injectionmeans being constituted by a source of fuel under pressure of which thedelivery circuit opening into the said portion of the inlet conduit iscontrolled by at least one valve actuated by an electromagnet, themetering system comprising a member driven in a movement of continuousrotation and capable, by acting on the energization of theelectromagnet, of determining over a fraction only of each of theserevolutions, the opening of the valve, said system being arranged sothat it increases the said fraction in proportion as the opening of theauxiliary throttle member increases and vice-versa, the said source offuel under pressure being constituted by a fuel pump in whose deliverycircuit acts a pressure regulator which comprises a relief valve tendingto open under the action of the delivery pressure of the pump and toclose under the action of the suction existing in the section of theinlet conduit comprised between its two throttle members, which suctionis transmitted through a connecting passage to a diaphragm to which therelief valve is coupled, characterized by the fact that an elasticelement which engages said relief valve and is deformable under theeffect of the variation of temperature, is arranged to exert on saidrelief valve, a force directed in the sense of its closing whichincreases (in algebraic value) in proportion as the temperaturedecreases.